1. Field of the Invention
The present invention relates to a handheld terminal device and a display control method therefor.
2. Description of the Related Art
Handheld terminal devices, such as cell phones and PDAs, have conventionally been provided with a display to show the content of communication. A number of arts have been proposed to make such display easier to see. For example, in order to display a short message sent to a cell phone on a larger screen for easier viewing, one of these arts proposes a television which includes a television function part, a cell phone function part, and a control part. In this television, when a short message arrives at the television function part, the control part sounds a ringtone, flashes the LED, and then shows the message on the TV screen in scrolling display (refer to Japanese Patent Laying-Open (Kokai) No. 2002-112139).
Another example of these arts proposes a communication terminal which has a camera part, consisting of a digital camera, and a cell phone part. This communication terminal stores images shot using the digital camera in a memory, for later view as necessary, on a display under the control of the cell phone part (refer to Japanese Patent Laying-Open (Kokai) No. 2000-295667).
Yet another example of these arts proposes a data processing unit wherein a first storing part stores pieces of image data that have been input by an image inputting part; an identification information assigning part assigns identification information for linkage between each piece of image data and a telephone number input by a telephone number inputting part; a second storing part stores a list of links among identification information, telephone number, and image data; and a screen display controlling part displays said image data, from which the user can select an image to make a phone call to the telephone number that is stored in the second storing part with a link to the selected image (refer to Japanese Patent Laying-Open (Kokai) No. 2001-273236).
Many other related arts have also been proposed. One example of these arts proposes a method which can eliminate the necessity for the user to associate a piece of image information with a telephone number and register them in a telephone directory, by automating the association between image information and text information and the registration of this association in the telephone directory (refer to Japanese Patent Laying-Open (Kokai) No. 2002-158981).
Another example of these arts proposes a handheld telephone which can display the portrait images of callers and other image data. This handheld telephone registers the telephone numbers of specific individuals as registered numbers, stores in a flash memory the still image data of these individuals shot using a digital camera, and stores in a RAM a table of registered numbers which contains associations between image data and registered number. When a call arrives, the telephone looks up the table of registered numbers to find if the telephone number matches with any of the registered numbers. If there is a match, the telephone then reads and outputs the image data associated with the matching registered number to the display (refer to Japanese Patent Laying-Open (Kokai) No. Heisei 10-327232).
Yet another example of these arts proposes a cell phone which allows the user to identify the caller by the color to which the display changes on the arrival of a call. In this cell phone, which is capable of changing the display screen into several colors, the user first registers in a telephone directory list other party IDs and their associated display colors. On the arrival of a call, the cell phone collates the caller ID detected with the other party IDs registered in the telephone directory and, if there is a match, it changes the display to the color associated with the matching other party ID (refer to Japanese Patent Laying-Open (Kokai) No. 2000-358086).
Yet another example of these arts proposes a highly convenient mobile radio terminal which allows the user to identify the caller easily on receiving a call or an email message. This mobile radio terminal stores, in a telephone directory data storing area, telephone directory data consisting of the names of possible other-end parties and their associated telephone numbers and email addresses. It also stores associations among identification information for different elements, including image data to be used for alert operation on receiving a call or an email message, ringtone and call signaling melody, background color, and vibration pattern to be generated by a vibrator. The mobile radio terminal stores image data associated with various kinds of identification information in the image data storing area, and data of multiple ringtones and call signaling melodies in the data ringtone storing area, respectively. When a call or an email message arrives, the control part of the terminal alerts the user by displaying multiple images as applicable according to the telephone directory data stored in the telephone data storing area (refer to Japanese Patent Laying-Open (Kokai) No. 2002-176679).
In conventional cell phones in which the chat function utilizing the email function is implemented, the user creates a list of individuals with whom the user may chat and registers in the list the images to be displayed on the chat dedicated screen. This means that, images shot using a digital camera and stored in the telephone directory, if any, cannot be used for chat; the user needs to register the existing images all over again as chat-dedicated images. None of the above-described arts recognize the technical issue of addressing the problematic inconvenience that images dedicated to communications in a specific conversation form like chat must be registered all over again even though these images already exist in the terminal for other purposes. As a result, these conventional arts do not make any suggestion as to in what way such technical issue may be solved.